Method of joining sheets



May 9, 1939.

I r f o O G A ATTORNEY o5.

Patented May 9, 1939 UNITED STATES PATENT OFFICE METHOD or JOININGsnan'rs Thomas E. Piazze, Milwaukee, Wis., assignor, by mesneassignments, to Marshall 8; Ilsley Bank, Milwaukee, Wis., a Wisconsinbank Application December 10, 1936, Serial No. 115,079

' 2 Glaims. (01. 154-42) wax or the like.

In general, an object of the present invention is to provide an improvedprocess of and appara-.

tus for joining wax coated fabric sheets, webs or the like, which isextremely simple but highly} efficient.

It has heretofore been proposed in connection with the manufacture ofpaper bags and the like, from ribbon or web stock such as wax coated 2oglassine paper, to improve the adhesive quality of the gum or glue andthe cohesive action of the wax at the seams, by applying to the zones ofcoaction suflicient heat to melt the wax while the union is beingeffected. Because of the inflammable nature of the wax coated paper, ithas heretofore been customary to avoid the use of direct contact flamesby utilizing either an electric heater having a hot plateengageable-directly with the wax coated overlapping edge portions of 80the advancing ribbon or web of stock, or a metallie rotary disk heatedby a flame'remote from the zone of direct engagement between the diskand the moving ribbon. In addition to these indirect heaters, it hasalso been proposed to remove the 35 wax by applying a solvent thereto,and while these prior methods may melt or remove a wax coatingsufllciently to produce a joint, if the ribbon is advanced very slowly,they will not melt or remove the wax sufliciently when the stock istraveling 40 at speeds such as are desirable and necessary forcommercial production, and the prior methods of heating and removal ofwax are therefore unsatisfactory for normal commercial use. I havediscovered that hot flames projected directly (5 against the wax coatededge portions of a shee or web prior to overlapping thereof, andpreferably before the adhesive is applied, will most effectively'meltthe wax even when the ribbon of stock is traveling at a high rate ofspeed, and

50 that the prompt application of fluent gum to-the molten wax insureseilective intermingling of the wax and adhesive at the zone ofoverlapping, and thus produces a perfect joint.

It is therefore a-more specific object of my pres-' ent invention toprovide an improved method of 'joining coacting portions of a wax orsimilarly coated sheet of paper or the like with the aid of flamesprojected directly against said portions while in motion and prior toapplication of the adhesive, whereby most effective and durable 5 seamsare produced.

Another specific object of my invention is to provide simple andeflicient apparatus for efiecting commercial exploitation of my improvedprocess, so that the seam or seams may be produced automatically andcontinuously at a high rate of A further specific object of thisinvention is the-provision of an improved process of and apparatus forquickly and effectively joining the opposite edges of a continuousribbon or web of stock such as wax coated glassine paper or the like, inorder to convert the ribbon into tubular form preparatory to theproduction of bags or envelopes therefrom. 2o

Still another specific object of my invention is the provision of a newand useful mode of uniting by combined adhesion and cohesion,predetermined portions of either the same or different sheets of fabric,the coacting portions of which 25 have been coated or impregnated withsubstance having a low melting point. These and other specific objectsand advantages of my present invention will be apparent from thefollowing detailed description.

A clear conception of the several steps constituting my new process andof the construction and operation of the improved apparatus foreffecting commercial exploitation of the process,

may be had by. referring to the drawing accompanying and forming a partof this specification wherein like reference characters designate thesame or similar parts in the several views.

Fig. l is a diagrammatic part sectional side elevation of one assemblagefor continuously join- 40 ing the opposite edges of a ribbon of waxcoated sheet material so as to convert the same into tubular form;

Fig. 2 is a diagrammatic, somewhat enlarged development of the portionof the ribbon being converted, showing the relative points ofapplication of the heat and of the adhesive thereto;

and 1 Fig. 3 is a further enlarged diagram depicting the mode ofapplication of a flame to the wax coating, and the effect thereof.

Although I, have shown my invention as being especially applicable forthe purposes of joining or uniting the opposite edge portions of asingle ri bon, or web of wax coated paper with the aid M of both heatand glue so as to produce a continuous tubular structure, it isnotintended to thereby unnecessarily restrict the scope, since some ofthe improved features may obviously be used advantageously intheproduction of seams between independent sheets of the same or of.different materials coated or impregnated with other substances.

Referring to the drawing, the improved seaming or joining apparatusshown therein comprises in general, a continuous relatively wide ribbon5 of wax coated sheet material such as paper adapted to be deliveredconstantly and at a high rate of speed from a supply roll 6 by means ofa succession of guiding rollers 1, 8, 9; a pair of laterally separatedgas jets I0, II formed and disposed to continuously project small gasflames I2, I3 respectively, directly against the opposite sides of theadjacent rapidly advancing opposite edge portions I4, I5 of the ribbon5; an ordinary. gum or adhesive applying rotor or disk I6 coacting withthe edge portion I5 of the ribbon immediately beyond the zone ofapplication of the flame I3 and adjacent to the uppermost roller 9; astationary former or folding mechanism I! for automatically overlappingthe edge portions I8, I 5 over each other; and a set of pressing andpull rollers I8 cooperable with the tubular ribbon 5 beyond themechanism II.

The roll 6 should ordinarily contain an abundant supply of the ribbon 5which is usually composed of thin paper wax coated on both sides withsubstance such as paraflin wax or other wax-like material having similarcharacteristics and especially having a relatively low melting point.The transporting rollers I8 may be simultaneously driven in any wellknown manner as by a'common propelling motor I9, and the gas supply jetsI0, I I may be provided with manually operable control valves 20, 2Irespectively and with an automatic control valve 22 which shouldpreferably be connected with the roller system in such a way that whenone of the rollers I, 8, 9, I 8 stops, the gas supply will beautomatically cut oil? by closure of the automatic valve 22 slightly inadvance of the final stoppage of the machine. This automaticinterruption of the gas supply and consequent elimination of the flamesI2, I3 may be effectedeither mechanically or electrically when the speedof travel of the ribbon 5 becomes dangerously low, and while I haveshown diagrammatically one type of automatic cut-off, other types may beemployed. As illustrated in Fig. 1, the automatic valve 22 is operableto open the same, by a magnet 23 which may be energized only when themotor I9 is operating to rotate the rollers I8 direct and the rollers I,8,-9, through the web, and the valve 22 will be closed immediately toshut ofl'the gas supply to both jets III, II by a spring 24 whenever thecircuit of the driving motor I9 and of the magnet 23, is interrupted;but the jets II), II may also be shut off manually by manipulation ofthe valves 20, 2 I.

The flames I2, I3 are preferably of limited size as shown in Fig. 3, inorder to produce molten wax areas confined in width to the ultimateoverlap, and the adhesive should preferably be applied quickly aftermelting of the wax has been effected. The adhesive applying disk I6which coacts with the edge portion of the ribbon 5 adjacent to theroller 9, is of relatively well-known construction, being constantlyrotatable and dipping into a basin 25 of relatively fluent glue or gumso as to constantly deposit a stream or band 26 of the adhesive onto theadjacent edge portion I5 of the advancing ribbon 5 directly beyond thezone of application of the flame I3 as clearly shown in Fig. 2. Thestationary forming mechanism II which is also of well knownconstruction, consists of a thin plate 21 beneath which the body of theribbon 5 is adapted to travel as it proceeds toward the pull rollers I8,and over-the top of which the edge portions of the ribbon arecontinuously folded to overlapping position and to form a tubularstructure by the forming mechanism I1, prior to the advancement of theribbon between the rollers I8. It is to be understood that the abovedescribed mechanisms are shown diagrammatically and that the structurethereof is subject to considerable variation in actual commercialpractice.

. II], II, the flames I2, I3 are constantly projected against theopposite sides of the ribbon adjacent the opposite edge portions I4, I 5thereof, and the wax near the opposite edges of the ribbon is thusquickly converted to molten condition as indicated by the cross hatchedareas of Fig. 2. Immediately thereafter, the constantly revolving diskI6 applies a band 26 of fluent adhesive to the molten wax along the edgeportion I5 of the ribbon 5, and this fluent adhesive quickly mixes orintermingles with the molten wax along the ribbon edge I5. The ribbon 5with the wax at the edge portions I4, I5 still in highly moltencondition, is thereafter advanced along the forming mechanism I 1, andthe edge portions M, I 5 are reversed and caused to overlap as clearlyindicated in Fig. 2. The molten wax of the edge portion I4 is thusbrought into contact with the mixture of molten wax and adhesive on theedge portion I5; thus forming a tubular ribbon which is subsequentlypassed between the pull rollers I8, which apply the final pressure tocomplete the joint. It will thus be noted that the melting of the waxalong the edge portions I4, I5

of the ribbon 5, the application of the adhesive band 26, and thesubsequent completion of the joint by overlapping of the edge portionsI4, I5, is effected automatically and continuously, and the rapidadvancement of the ribbon 5 will positively prevent ignition of theinflammable ribbon 5 because the ribbon is not subjected to the flamesI2, I I3 for a sufficient length of time to eifect ignition of thematerial.

If, for any reason, one or more of the guiding and advancing rollersshould stop, the flames I2, I3 will be automatically extinguished byvirtue of the closing of the supply valve 22. Upon stoppage of themachine, and extinguishing of the flames I 2, I3, the valves 20, 2Ishould also preferably be closed until after the machine has beenre-started. The valve 22 will then open automatically, whereupon thevalves 20, 2I may be opened and the jets I0, II may be re-ignited. Whileit is preferable to utilize adhesive in conjunction with the molten waxcoatings, a joint may be formed by utilizing the molten wax coatingsalone, and when the adhesive is employed, it is preferable to apply thegum or glue in relatively fluent condition to one of the molten waxsurfaces rather promptly after the melting has taken place.

From the foregoing description of the present invention, it will beapparent that I have provided a simple and highly eflicient method ofproducing joints with the aid of flames which may be projected directlyagainst the surfaces of inflammable sheet material. The improved methodmay be utilized to join either remote parts of the same sheet or ribbon,or portions-of separate sheets or ribbons, and while it may bepreferable to melt the wax on both of the sheet portions which aresubsequently brought to-v gether, it may also be possible to obviate oneof the melting operations. By applying the adhesive to the molten wax asquickly as possible,

thorough mixing and intermingling of the wax,

and adhesive will be assured, thereby improving the final joint, andwhile the final pressing operation may be dispensed with, this pressingwill serve to more effectively distribute the adhesive, and will therebyalso improve the joint. .The feature of extinguishing the flames whenthe advancing movement of the ribbon 5 ceases, insures protectionagainst possible fire, and permits safe use of the present process inconjunction with rather highly inflammable materials, and my improvedprocess has proven highly practical, eflicient, and safe in actual use.I have found that the use of the flames-l2, l3 projected directlyagainst the wax coatings, permits advancement of the ribbon 5 atrelatively high speed and with sufficient rapidity so as to makecommercial production possible, and this result has never heretoforebeen attained with the use of indirect heaters of the electrical andmechanical types which depend upon a heated surface contacting with andmelting the wax coatings.

It should be understood that it is not desired to limit this inventionto the exact details of construction of the apparatus, and to theprecise steps of the process herein shown and described, for variousmodifications within the scope of the claims may occur to personsskilled in the art.

I claim:

1. The method of continuously forming a tube from a web of thin waxcoated paper sheet material for the subsequent manufacture of bags,which consists in feeding the web at high speed along a longitudinalpath of travel, projecting a flame of high heat intensity and limitedsize against the side-edges of the web and respectively on oppositesurfaces thereof to melt the wax and produce a narrow molten wax areaparallel with the side margins of and on opposite surfaces of the web,there being no wax removed from said area by reason of the high speed ofthe I web travel, immediately thereafter applying a narrow strip offluent adhesive to the advancing molten wax area at one edge portion ofthe web to cause the adhesive to mingle with the molten wax, overlappingsaid opposite marginal portions of the web to bring the molten wax areaof one surface into direct engagement with the mixture of molten wax andadhesive on the opposite surface, pressing the overlapped surfaces intointimate contact with each other before the adhesive and wax have set toproduce an adhesively secured and wax protected joint after the adhesiveand wax have set.

2. The method of continuously forming a tubefrom a web of thin waxcoated paper sheet material for the subsequent manufacture of bags,whichconsists in feeding the web at high speed along a longitudinal-pathof traVeL'projecting a flame of high heat intensity and limited sizeagainst the side edges of the web and respectively on oppositesurfacesthereof to melt the wax and produce a narrow molten wax area parallelwith the side margins of and on opposite surfaces of the web, therebeing no wax removed from said area by reason of the high speed of theweb travel, immediately thereafter applying a narrow strip of fluentadhesive to the advancing molten wax area at one edge portion of the webto cause the adhesive to mingle with themolten wax, overlapping saidopposite marginal portions of the web to bring the molten wax area ofone surface into direct engagement with the mixture of molten wax andadhesive on the opposite surface, pressing the overlapped surfaces intointimate contact with each other before the adhesive and wax have set toproduce an adhesively secured and wax protected joint after the adhesiveand wax have set, and controlling the application of said flame insynchronism with the speed of travel of the advancing web so that whenthe movement of the web is reduced to a speed whereby ignition wouldoccur, the flame is automatically extinguished.

THOMAS E. PIAZZE.

